Low contamination components for semiconductor processing apparatus and methods for making components

ABSTRACT

Components of semiconductor processing apparatus axe formed at least partially of erosion, corrosion and/or corrosion-erosion resistant ceramic materials. Exemplary ceramic materials can include at least one oxide, nitride, boride, carbide and/or fluoride of hafnium, strontium, lanthanum oxide and/or dysprosium. The ceramic materials can be applied as coatings over substrates to form composite components, or formed into monolithic bodies. The coatings can protect substrates from physical and/or chemical attack. The ceramic materials can be used to form plasma exposed components of semiconductor processing apparatus to provide extended service lives.

This application is a divisional application of U.S. application Ser.No. 12/230,413 entitled LOW CONTAMINATION COMPONENTS FOR SEMICONDUCTORPROCESSING APPARATUS AND METHODS FOR MAKING COMPONENTS, filed on Aug.28, 2008 which is a continuation of U.S. application Ser. No. 10/837,575entitled LOW CONTAMINATION COMPONENTS FOR SEMICONDUCTOR PROCESSINGAPPARATUS AND METHODS FOR MAKING COMPONENTS, filed on May 4, 2004 whichis a divisional application of U.S. application Ser. No. 10/101,701entitled LOW CONTAMINATION COMPONENTS FOR SEMICONDUCTOR PROCESSINGAPPARATUS AND METHODS FOR MAKING COMPONENTS, filed on Mar. 21, 2002, theentire content of each is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to components for semiconductor materialprocessing equipment. The components are formed of materials that canreduce contamination during semiconductor material processing. Theinvention also relates to methods of making the components.

2. Description of the Related Art

In the field of semiconductor material processing, vacuum processingchambers are used for etching and chemical vapor deposition (CVD) ofmaterials on substrates. Process gases are flowed into the processingchamber while a radio frequency (RF) field is applied to the processgases to generate a plasma of the process gases. The plasma performs thedesired etching or deposition of selected materials on wafers. Examplesof parallel plate, transformer coupled plasma (TCP™), which is alsocalled inductively coupled plasma (ICP), and electron-cyclotronresonance (ECR) reactors and components thereof are disclosed incommonly owned U.S. Pat. Nos. 4,340,462; 4,948,458; 5,200,232 and5,820,723.

During processing of semiconductor substrates, the substrates aretypically held in place within the vacuum chamber by substrate holders,as disclosed, for example, in U.S. Pat. Nos. 5,262,029 and 5,838,529.Process gas can be supplied to the chamber by various gas supplysystems.

In addition to the plasma chamber equipment, other equipment used inprocessing semiconductor substrates includes transport mechanisms,liners, lift mechanisms, load locks, door mechanisms, robotic aims,fasteners, and the like.

Plasmas are used to remove materials by etching or for deposition ofmaterials on substrates. The plasma etch conditions create significantion bombardment of the surfaces of the processing chamber that areexposed to the plasma. This ion bombardment, combined with plasmachemistries and/or etch byproducts, can produce significant erosion,corrosion and corrosion-erosion of the plasma-exposed surfaces of theprocessing chamber. As a result, the surface materials are removed byphysical and/or chemical attack, including erosion, corrosion and/orcorrosion-erosion. This attack causes problems including shortpart-lifetimes, increased consumable costs, particulate contamination,on-wafer transition metal contamination and process drift.

In light of these problems, plasma processing chambers have beendesigned to include parts, such as, disks, rings, and cylinders, thatconfine the plasma over the wafer being processed. However, these partsare continuously attacked by the plasma and, consequently, ultimatelyerode or accumulate polymer buildup. Eventually, these parts suffer suchwear that they are no longer usable. Those parts with relatively shortlifetimes are commonly referred to as “consumables.” If the consumablepart's lifetime is short, then the cost of ownership is high. Erosion ofconsumables and other parts generates contamination in plasma processingchambers.

Because of the erosive and corrosive nature of the plasma environment insuch reactors, and the need to minimize particle and/or metalcontamination, it is desirable for components of such equipment,including consumables and other parts, to have suitably high erosion andcorrosion resistance. Known parts have been formed of aluminum-basedmaterials. However, the high ion bombardment by the plasma can erode andcorrode these materials, producing unsatisfactory levels ofcontamination (e.g., particulate contamination and metallic impuritycontamination).

In view of the high purity requirements for processing semiconductormaterials there is a need for components of semiconductor processingapparatus composed of materials that provide improved resistance tophysical and chemical attack, including erosion, corrosion and/orerosion-corrosion, to minimize the associated contamination ofsemiconductor materials during their processing. Materials that canincrease the service life of components of the equipment and thus reducethe down time of the apparatus, would contribute to reducing the cost ofprocessing semiconductor materials.

SUMMARY OF THE INVENTION

The invention can satisfy the above-described needs, as well as otherneeds, by providing components of semiconductor processing apparatuscomposed of ceramic materials that provide improved wear resistance toerosion, corrosion and/or corrosion-erosion in plasma processingenvironments. The components can provide low contamination with respectto metals and particulate.

In accordance with exemplary embodiments of the invention, the ceramicmaterials can be applied as coatings on surfaces of substrates, incomponents utilized in semiconductor material processing equipment. Forexample, the components can be used in plasma processing chambers. Thecoated components can provide improved resistance to erosion, corrosionand/or corrosion-erosion when exposed to plasmas during processing.

In accordance with other exemplary embodiments of the invention, suchcomponents can be bulk parts formed entirely of the protectivematerials. That is, the components can be monolithic.

An exemplary embodiment of a process of making a component of asemiconductor processing apparatus according to the invention comprisesforming at least a portion of a component of such equipment from aceramic material. The portion comprises an outermost surface of thecomponent. The ceramic material comprises (i) at least one oxide,nitride, boride, carbide and/or fluoride of (ii) strontium, lanthanumand dysprosium, and/or at least one nitride, boride, carbide and/orfluoride of hafnium. Preferably, the ceramic material comprises one ofstrontium oxide, dysprosium oxide and lanthanum oxide as the singlelargest constituent of the ceramic material coating. The ceramicmaterial can be applied as a coating, or it can be formed into amonolithic body.

Another exemplary embodiment of the invention comprises applying acoating of a ceramic material over a metal containing or polymericsurface of a component of a semiconductor processing apparatus. Theceramic material comprises hafnium oxide, hafnium nitride, hafniumboride, hafnium carbide or hafnium fluoride as the single largestconstituent of the ceramic material coating.

Other exemplary embodiment of methods according to the inventioncomprise forming a component of a semiconductor processing apparatus inthe form of a monolithic body. The component comprises hafnium oxide,hafnium nitride, hafnium boride, hafnium carbide or hafnium fluoride asthe single largest constituent.

An exemplary embodiment of a process of making a component of asemiconductor processing apparatus according to the invention comprisespreparing a slurry comprising as the single largest constituent (i) atleast one oxide, nitride, boride, carbide and/or fluoride of (ii)strontium, lanthanum and dysprosium, and/or at least one nitride,boride, carbide and/or fluoride of hafnium; forming a green compact fromthe slurry in the desired shape; and sintering the green compact to forma component. The ceramic material preferably comprises at the least oneof hafnium. oxide, strontium oxide, dysprosium oxide and lanthanum oxideas the single largest constituent thereof These processes can be used toform monolithic components.

An exemplary embodiment of a component of a semiconductor processingapparatus according to the invention comprises at least a portioncomprising a ceramic material. The portion comprises an outermostsurface of the component. The ceramic material comprises as the singlelargest constituent (i) at least one oxide, nitride, boride, carbideand/or fluoride of (ii) strontium, lanthanum and dysprosium, and/or atleast one nitride, boride, carbide and/or fluoride of hafnium.

Another exemplary embodiment of a component of a semiconductorprocessing apparatus according to the invention comprises a substratehaving a metal containing or polymeric surface; and a coating of aceramic material over the surface, where the ceramic material compriseshafnium oxide, hafnium nitride, hafnium boride, hafnium carbide orhafnium fluoride as the single largest constituent of the ceramicmaterial coating.

Another exemplary embodiment of a component of a semiconductorprocessing apparatus according to the invention comprises a monolithicbody, which comprises hafnium oxide, hafnium nitride, hafnium boride,hafnium carbide or hafnium fluoride as the single largest constituent.

The invention also provides semiconductor processing apparatus thatincludes at least one of above-described components to provide wearresistance.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be readily understood by the following detaileddescription in conjunction with the accompanying drawings.

FIG. 1 illustrates a conventional plasma spray process.

FIG. 2 shows a cross-sectional view of a gas ring for a plasma etchingapparatus according to an exemplary embodiment of the invention.

FIG. 3 shows an etch chamber containing exemplary embodiments ofcomponents according to the invention.

FIG. 4 shows another etch chamber containing exemplary embodiments ofcomponents according to the invention.

FIG. 5 shows an exemplary embodiment of a protective ceramic coatingaccording to the invention.

FIG. 6 shows another exemplary embodiment of a protective ceramiccoating according to the invention.

FIG. 7 shows an exemplary embodiment of a monolithic component accordingto the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention provides components that have wear resistance with respectto physical and chemical attack by plasmas generated in semiconductormaterial processing apparatuses. As used herein, the term “wearresistant” includes, but is not limited to, erosion, corrosion and/orcorrosion-erosion resistance. The components are composed of wearresistant ceramic materials.

In some exemplary embodiments, the components include coatings composedof erosion resistant ceramic materials formed on substrates. Forexample, the components can include substrates and one or more erosionresistant ceramic coatings formed on the substrates. The coatings resisterosion and, being non-metallic materials, are also resistant tocorrosion and/or corrosion-erosion.

In other exemplary embodiments of the invention, the components canconsist essentially of wear resistant ceramic materials. For example,the components can be bulk parts of a semiconductor material processingapparatus.

According to the invention, the components composed of the wearresistant ceramic materials can be components of apparatuses forprocessing semiconductors.

The invention also provides semiconductor processing apparatuses thatinclude one or more of the components composed, at least partially, of awear resistant material.

In addition, the invention provides methods of making components, atleast in part, of the wear resistant materials.

As stated above, the invention is applicable to any suitable type ofcomponent. The invention provides effective wear resistance to thesurfaces of components of semiconductor material processing apparatuses.Those skilled in the art will appreciate that the wear resistantmaterials according to the invention can be applied to differentprocessing apparatuses useful for processing different semiconductormaterials. In addition, the wear resistant materials can be applied todifferent components in the processing apparatuses. Such exemplarycomponents include, but are not limited to, parts of a plasma and/orvacuum chamber, such as, for example, chamber walls, substrate supports,gas distribution systems including showerheads, baffles, rings, nozzles,etc., fasteners, heating elements, plasma screens, liners, transportmodule components, such as robotic arms, fasteners, inner and outerchamber walls, and the like.

According to the invention, the wear resistant materials can comprise atleast one of hafnium, strontium, dysprosium and lanthanum. Theseelements have a relatively large molecular mass and are relatively inertwith respect to typical etching chemicals, which are believed to providea reduced erosion rate in plasma environments. Preferably, the wearresistant materials comprise one of hafnium oxide, strontium oxide,dysprosium oxide or lanthanum oxide as the single largest constituent ofthe ceramic material. Exemplary embodiments of the ceramic materials cancomprise any one or more of these oxides. Other constituents that can beincluded in the ceramic materials are described in detail below.

The hafnium containing ceramic materials according to the inventionpreferably contain hafnium oxide (hafnium) as the single largestconstituent. In some embodiments, the hafnium containing ceramicmaterials can consist essentially of hafnium oxide. The hafniumcontaining ceramic materials can also contain other hafnium containingceramic materials other than oxides, including, but not limited to, atleast one hafnium boride, hafnium fluoride, hafnium nitride and/orhafnium carbide, or mixtures thereof.

According to the invention, the hafnium containing ceramic materials cancontain other ceramic materials other than, or in addition to, theabove-described hafnium oxide, boride, fluoride and carbide materials.These other ceramic materials can include, but are not limited to, atleast one oxide, nitride, boride, fluoride and/or carbide of elementsselected from Groups IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB,IIIB, IVB and VB of the periodic table; and/or one or more oxide,nitride, boride, fluoride or carbide of any element of the lanthanideseries (i.e., elements having an atomic number of 58-71). For example,hafnium containing ceramic materials (and also strontium containing,dysprosium containing and lanthanum containing materials describedbelow) can be mixed with yttrium oxide (yttria), zirconium oxide(zirconia), aluminum oxide (alumina) and/or cerium oxide (ceria).

The strontium containing ceramic materials according to the inventionpreferably contain strontium oxide (strontia) as the single largestconstituent. In some embodiments, the strontium containing ceramicmaterials can consist essentially of strontium oxide. The strontiumcontaining ceramic materials can also contain other strontium containingceramic materials other than oxides, including, but not limited to, atleast one strontium boride, strontium fluoride, strontium nitride,strontium carbide, or mixtures thereof.

According to the invention, the strontium containing ceramic materialscan contain other ceramic materials other than, or in addition to, theabove-described strontium oxide, boride, fluoride and carbide materials.These other ceramic materials can include, but are not limited to, oneor more oxides, nitrides, borides, fluorides and carbides of elementsselected from Groups IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIB,IVB, and VB of the periodic table; and/or one or more oxide, nitride,boride, fluoride or carbide of any element of the lanthanide series, asdescribed above.

The dysprosium containing ceramic materials according to the inventionpreferably contain dysprosium oxide (dysprosia) as the single largestconstituent. In some embodiments, the dysprosium containing ceramicmaterials can consist essentially of dysprosium oxide. The dysprosiumcontaining ceramic materials can also contain other dysprosiumcontaining ceramic materials other than oxides, including, but notlimited to, at least one dysprosium boride, dysprosium fluoride,dysprosium nitride, dysprosium carbide, or mixtures thereof.

According to the invention, the dysprosium containing ceramic materialscan contain other ceramic materials other than, or in addition to, theabove-described dysprosium oxide, boride, fluoride and carbidematerials. These other ceramic materials can include, but are notlimited to, at least one oxide, nitride, boride, fluoride and/or carbideof elements selected from Groups IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA,IB, IIB, IIIB, IVB and VB of the periodic table; and/or one or moreoxide, nitride, boride, fluoride or carbide of any element of thelanthanide series, as described above.

The lanthanum containing ceramic materials according to the inventionpreferably contain lanthanum oxide (lanthana) as the single largestconstituent. In some embodiments, the lanthanum containing ceramicmaterials can consist essentially of lanthanum oxide. The lanthanumcontaining ceramic materials can also contain other lanthanum containingceramic materials other than oxides, including, but not limited to, atleast one lanthanum boride, lanthanum fluoride, lanthanum nitride and/orlanthanum carbide, or mixtures thereof.

According to the invention, the lanthanum containing ceramic materialscan contain other ceramic materials other than, or in addition to, theabove-described lanthanum oxide, boride, fluoride and carbide materials.These other ceramic materials can include, but are not limited to, atleast one oxide, nitride, boride, fluoride and/or carbide of elementsselected from Groups IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB,IIIB, IVB, and VB of tie periodic table; and/or at least one oxide,nitride, boride, fluoride and/or carbide of any element of thelanthanide series, as described above.

According to the invention, the ceramic materials can comprise mixturesof the above-described hafnium, strontium, dysprosium and lanthanumcontaining materials. In addition, the ceramic materials can comprisemixtures of hafnium, strontium, dysprosium and/or lanthanum containingmaterials, and additional materials, including, but not limited to, oneor more oxides, nitrides, borides, fluorides and carbides of elementsselected from Groups IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB,IIIB, IVB, and VB; and/or one or more oxide, nitride, boride, fluorideor carbide of any element of the lanthanide series, as described above.

In order to try to minimize the contamination of electronic materialsprocessed in equipment incorporating one or more hafnium, strontium,dysprosium and/or lanthanum containing components according to theinvention, it is desirable for the ceramic materials to be as pure aspossible, e.g., include minimal amounts of potentially contaminatingelements, such as transition metals, alkali metals or the like. Forexample, the hafnium, strontium, dysprosium and lanthanum containingceramic materials can be sufficiently pure to avoid on-wafercontamination of 10¹⁰ atoms/cm² or higher, preferably 10⁵ atoms/cm² orhigher. Preferably, these ceramic materials have a purity of at leastabout 99%, and more preferably from about 99.99% to about 100%.

In addition, the hafnium, strontium, dysprosium and lanthanum containingceramic materials according to the invention have a smooth surfacefinish. Preferably, these materials, applied as coatings or formed intomonolithic components, have a surface roughness (RA) of from about 5 toabout 400 μinch, and more preferably less than about 200 μinch.

The hafnium, strontium, dysprosium and lanthanum containing ceramicmaterials according to the invention can also provide a high bondstrength to the underlying substrate. Preferably, these materialsapplied as coatings have a tensile bond strength of from about 2000 psito about 7000 psi.

Also, the hafnium, strontium, dysprosium and lanthanum containingceramic materials according to the invention can provide low porositylevels, which is advantageous to minimize contact of aggressiveatmospheres (e.g., HCl containing atmospheres) with the underlyingsubstrate, and thus subsequent corrosion, erosion and/orcorrosion-erosion of the substrate by the aggressive atmosphere.Preferably, the ceramic materials have a porosity of less than 15% byvolume, and more preferably less than about 3% by volume.

In addition, the hafnium, strontium, dysprosium and lanthanum containingceramic materials according to the invention can provide a high hardnessto resist erosion. Preferably, the ceramic materials have a hardness(HVO₃) of from about 200 to about 800.

The above-described ceramic materials can provide desirable wearresistance properties for use in semiconductor processing apparatus,such as, for example, plasma etch chambers. In particular, hafnium,strontium, dysprosium and lanthanum containing ceramic materials canprovide surfaces that can reduce ion induced erosion and associatedlevels of particulate contamination in plasma reactor chambers. hafnium,strontium, dysprosium and lanthanum containing ceramic materials canalso protect underlying substrates against both physical attack andchemical attack by plasmas.

The wear resistant ceramic materials according to the invention can be-used in various different plasma atmospheres for etching and depositionapplications, as well as other uses. For example, typical etchchemistries include, for example, chlorine containing gases including,but not limited to, Cl₂, HCl and BCl₃; bromine containing gasesincluding, but not limited to, bromine and HBr; oxygen containing gasesincluding, but not limited to, O₂, H₂O and SO₂; fluorine containinggases including, but not limited to, CF₄, CH₂F₂, NF₃, CH₃F, CHF₃ andSF₆; and inert and other gases including, but not limited to He, Ar andN₂. These and other gases may be used in any suitable combination,depending on the desired plasma. Exemplary plasma reactor etchingoperating conditions are as follows: temperature of from about 25° C. toabout 90° C.; pressure of from about 0 mTorr to about 100 mTorr; gasflow rate of from about 10 sccm to about 1000 sccm; and plasma power offrom about 0 Watts to about 1500 Watts.

In an exemplary preferred embodiment of the invention, the hafnium,strontium, dysprosium and lanthanum containing ceramic materials areprovided as a coating on a substrate. These coatings can be applied bymethods known in the art. A preferred coating method is thermal spraying(e.g., plasma splaying). In this method, ceramic powder is melted andincorporated in a gas stream, which is directed at the component beingspray coated. An advantage of thermal spraying techniques is that thecomponent is coated only on the sides facing the thermal spray gun, andmasking can be used to protect other areas. Conventional thermalspraying techniques, including plasma spraying, are described in TheScience and Engineering of Thermal Spray Coating by Pawlowski (JohnWiley, 1995). This description is hereby incorporated by reference inits entirety.

A particularly preferred thermal spraying method is plasma spraying.Plasma spraying can be used to coat even intricate interior surfaces ofchambers and other chamber components. FIG. 1 illustrates a typicalplasma spraying process. The coating material, usually in the form of apowder 112, is injected into a high temperature plasma flame 114 usuallyvia an external powder port 132 The powder is rapidly heated andaccelerated to a high velocity. The hot material impacts on thesubstrate surface 116 and rapidly cools to form a coating 118.

The plasma spray gun 120 comprises an anode 122 and a cathode 124, bothof which are water cooled. Plasma gas 126 (e.g., argon, nitrogen,hydrogen, helium) flows around the cathode in the direction generallyindicated by arrow 128 and through a constricting nozzle of the anode.The plasma is initiated by a high voltage discharge, which causeslocalized ionization and a conductive path for a DC arc to form betweenthe cathode 124 and the anode 122. Resistance heating from the arccauses the gas to form a plasma. The plasma exits the anode nozzleportion as a free or neutral plasma flame (plasma which does not carryelectric current). When the plasma is stabilized ready for spraying, theelectric arc extends down the nozzle. The powder 112 is so rapidlyheated and accelerated that the spray distance 136 between the nozzletip and the substrate surface can be on the order of 125 to 150 mm.Plasma sprayed coatings are produced by molten or heat-softenedparticles caused to impact on the substrate surface 116.

According to the invention, surface treating techniques, such ascleaning and particle blasting can be used to provide a more chemicallyand physically active surface for bonding. Prior to coating, the surfaceof the substrate is preferably thoroughly cleaned to remove undesirablesurface material, such as oxides or grease. The surface can also beroughened by any suitable method, such as grit blasting, prior tocoating. This roughening increases the surface area available forbonding, which increases the coating bond strength. The rough surfaceprofile can also promote mechanical keying or interlocking of thecoating with the substrate.

For aluminum reactor components, it is preferable to anodize the surfaceof the component that is to be coated prior to coating, but not roughenthe anodized surface. The anodized layer provides an additional barrier,i.e. in addition to protection provided by the coating, againstcorrosive attack of the underlying aluminum. The anodized aluminum layerformed on aluminum substrates, such as 6061-T6 aluminum, can have anysuitable thickness. For example, the thickness can be typically be fromabout 2 mil to about 10 mil. The anodized surface can have any suitablefinish. For example, the surface finish can have an RA value of about 20μinch to about 100 μinch. The anodized layer call be sealed by anysuitable technique, such as by using boiling deionized water.

Hafnium oxide, strontium oxide, dysprosium oxide and/or lanthanum oxidecontaining ceramic materials according to the invention are preferablyapplied using a plasma spray process. However, any other coating methodsuitable for use with ceramic materials may also be employed. Forexample, the hafnium oxide, strontium oxide, dysprosium oxide and/orlanthanum oxide containing ceramic coatings can also be applied bysputtering, sputter deposition, immersion coating, chemical vapordeposition, evaporation and condensation (including election beamevaporation and condensation), physical vapor deposition, hot isostaticpressing, cold isostatic pressing, compression molding, casting,compacting and sintering, and thermal spraying.

In some preferred embodiments of the invention, the hafnium, strontium,dysprosium and/or lanthanum containing ceramic components are used in ahigh-density plasma reactor. An exemplary reactor of this type is theTCP 9400™ plasma etch reactor available from Lam Research Corporation ofFremont, Calif. In the TCP 9400™ reactor, processing gases (such as Cl₂,HBr, CF₄, CH₂F₂, O₂, N₂, Ar, SF₆ and NF₃) are conducted into a gas ringlocated at the bottom of the etch chamber and are then guided throughgas holes into the reactor chamber. FIG. 2 shows a gas ring for a TCP9400™ etch reactor. As shown in FIG. 2, the main body of the gas ring 40surrounds a substrate support 44. The bottom surface of the gas ring 40contains a ring-shaped gas-guiding trench 60. The aforementioned gasholes 50 extend into the gas-guiding trench 60.

The gas ring 40 is typically composed of aluminum. Upper surfaces of thegas ring are directly exposed to the plasma and thus subject to erosion,corrosion and corrosion-erosion. To protect these surfaces, the gas ringis typically covered with an aluminum oxide layer. This layer is,however, relatively brittle and can crack during repeated thermalcycling of the reactor during use. Cracks that form in the anodizedlayer can allow the corrosive process gases to attack the underlyingaluminum layer, reducing part life and contributing to metallic andparticle contamination of processed substrates, such as wafers, flatpanel display substrates and the like.

According to exemplary embodiments of the invention, the exposedsurfaces of the gas ring can be covered with a coating 42 of a hafnium,strontium, dysprosium and/or lanthanum containing ceramic material. Theceramic materials can be coated on a bare (with or without a nativeoxide surface film) aluminum layer or on an aluminum oxide layer (e.g.,aluminum having an anodized surface). When coating the gas ring, thecoating can be allowed to partially penetrate into the gas holes to coatand protect the inside walls thereof, but without obstructing theopenings. For example, the gas holes can be plugged or masked during thecoating process.

Other components of the TCP 9400™ etch reactor that can be exposed tothe plasma during processing can also be coated with a hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialaccording to the invention. These components include, for example,chamber walls, chamber liners, chucking devices and the dielectricwindow opposite the substrate. Providing a coating according to theinvention on the upper surface of a chucking device, such as anelectrostatic chuck, provides additional protection to the chuck duringcleaning cycles in which a wafer is not present and the upper surface ofthe chuck is thus directly exposed to the plasma.

Another exemplary polysilicon etch reactor that can include the hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialsaccording to the invention is the Versys™ Polysilicon Etcher or 2300™etcher also available from Lam Research Corporation of Fremont, Calif.,as shown in FIG. 3. The reactor comprises a reactor chamber 150 thatincludes a substrate support 152 including an electrostatic chuck 154,which provides a clamping force to a substrate (not shown) mountedthereon. A focus ring 170 is mounted on the substrate support 152 aroundthe electrostatic chuck 154. The substrate support 152 can also be usedto apply an RF bias to the substrate. The substrate can also beback-cooled rising a heat transfer gas such as helium. In the 2300™etcher, processing gases (e.g., Cl₂, HBr, CF₄, CH₂F₂, O₂, N₂, Ar, SF₆ orNF₃) are introduced into the chamber 150 via a gas injector 168 locatedon the top of chamber 150 and connected to a gas feed 156. The gasinjector 168 is typically made of quartz or a ceramic material such asalumina. As shown, an inductive coil 158 can be powered by a suitable RFsource (not shown) to provide a high density (e.g., 10¹¹-10¹² ions/cm³)plasma. The inductive coil 158 couples RF energy through dielectricwindow 160 into the interior of chamber 150. The dielectric window 160is typically made of quartz or alumina. The dielectric window 160 isshown mounted on an annular member 162. The annular member 162 spacesdielectric window 160 from the top of chamber 150 and is referred to asa “gas distribution plate”. A chamber liner 164 surrounds the substratesupport 152. The chamber 150 can also include suitable vacuum pumpingapparatus (not shown) for maintaining the interior of the chamber at adesired pressure.

In FIG. 3, selected internal surfaces of reactor components, such as theannular member 162, dielectric window 160, substrate support 152,chamber liner 164, gas injector 168, focus ring 170 and theelectrostatic chuck 154, are shown coated with a coating 166 of ahafnium, strontium, dysprosium and/or lanthanum containing ceramicmaterial according to the invention. As shown in FIG. 3, selectedinterior surfaces of the chamber ISO and substrate support 152 below thechamber liner 164 can also be provided with a coating 166 of a hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialaccording to the invention. Any or all of these surfaces, as well as anyother internal reactor surface, can be provided with a coating accordingto the invention. As described below, any or all of these components canalternatively be manufactured from monolithic bodies of a hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialaccording to the invention.

According to the invention, the components can be used in a high-densityoxide etch process. An exemplary oxide etch reactor is the TCP 9100™plasma etch reactor available from Lam Research Corporation of Premont,Calif. In the TCP 9100™ reactor, the gas distribution plate is acircular plate situated directly below the TCP™ window, which is alsothe vacuum sealing surface at the top of the reactor in a plane aboveand parallel to a semiconductor wafer. The gas distribution plate issealed to a gas distribution ring located at the periphery of the gasdistribution plate. The gas distribution ring feeds gas from a sourceinto the volume defined by the gas distribution plate, an inside surfaceof a window underlying an antenna in the form of a flat spiral coilsupplying RF, energy into the reactor, and the gas distribution ring.The gas distribution plate contains holes of a specified diameter, whichextend through the plate. The spatial distribution of the holes throughthe gas distribution plate can be varied to optimize etch uniformity ofthe layers to be etched, e.g., a photoresist layer, a silicon dioxidelayer and an underlayer material on the wafer. The cross-sectional shapeof the gas distribution plate can be varied to manipulate thedistribution of RF power into the plasma in the reactor. The gasdistribution plate is a dielectric material to enable coupling of thisRF power through the gas distribution plate into the reactor. Further,it is desirable for the material of the gas distribution plate to behighly resistant to chemical sputter-etching in environments, such asoxygen or a hydro-fluorocarbon gas plasma, to avoid breakdown and theresultant particle generation associated therewith.

FIG. 4 illustrates a plasma reactor of the aforementioned type. Thereactor comprises a reactor chamber 10. A substrate holder 12 includesan electrostatic chuck 34, which provides a clamping force and an RFbias to a substrate 13, The substrate can be back-cooled using a heattransfer gas such as helium. A focus ring 14 confines plasma in a regionabove the substrate. A source of energy for maintaining a high density(e.g., 10¹⁰-10¹² ions/cm³) plasma in the chamber, such as an antenna 18powered by a suitable RF source to provide a high density plasma, isdisposed at the top of the reactor chamber 10. The reactor chamberincludes a vacuum pumping apparatus for maintaining the interior of thechamber at a desired pressure (e.g., below 50 mTorr, typically 1-20mTorr).

A substantially planar dielectric window 20 is provided between theantenna 18 and the interior of the processing chamber 10 and forms thevacuum wall at the top of the processing chamber 10. A gas distributionplate 22 is provided beneath window 20 and includes openings fordelivering process gas from the gas supply 23 to the chamber 10. Aconical liner 30 extends from the gas distribution plate 22 andsurrounds tie substrate holder 12. The antenna 18 can be provided with achannel 24 through which a temperature control fluid is flowed via inletand outlet conduit 25, 26. However, the antenna 18 and/or window 20 neednot be cooled, or could be cooled by other suitable technique, such asby blowing gas over the antenna and window, passing a cooling fluidthrough or in heat transfer contact with the window and/or gasdistribution plate, etc.

In operation, a substrate, such as a semiconductor wafer, is positionedon the substrate holder 12 and held in place by an electrostatic chuck34. Other clamping means, however, such as a mechanical clampingmechanism can also he used. Additionally, helium back-cooling can beemployed to improve heat transfer between the substrate and chuck.Process gas is then supplied to the vacuum processing chamber 10 bypassing the process gas through a gap between the window 20 and the gasdistribution plate 22. Suitable gas distribution plate arrangements(i.e., showerhead) arrangements are disclosed in commonly owned U.S.Pat. Nos. 5,824,605; 6,048,798; and 5,863,376, each of which isincorporated herein by reference in its entirety. A high density plasmais ignited in the space between the substrate and the window bysupplying suitable RF power to the antenna 18.

In FIG. 4, the internal surfaces of reactor components, such as the gasdistribution plate 22, the chamber liner 30, the electrostatic chuck 34,and the focus ring 14 are coated with a coating 32 of a hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialaccording to the invention. However, only selected ones of thesesurfaces, and/or other surfaces, can be coated with a hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialaccording to the invention.

Those skilled in the art will appreciate that the high densitypolysilicon and dielectric etch chambers described above are onlyexemplary embodiments of plasma etch reactors that can incorporatecomponents according to the invention. Components containing hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialsaccording to the invention can be used in any etch reactor (e.g., ametal etch reactor) or other type of semiconductor processing apparatuswhere the reduction of plasma induced erosion, corrosion and/orcorrosion-erosion and associated contamination is desired.

For example, other components that can be provided with a coating of ahafnium, strontium, dysprosium and/or lanthanum containing ceramicmaterial according to the invention include, but are not limited to,chamber walls, substrate holders, fasteners, etc. These parts aretypically made from metal (e.g., aluminum) or ceramic (e.g., alumina).These metallic plasma reactor components are typically exposed to plasmaand often show signs of erosion, corrosion and/or corrosion-erosion.Other parts that can be coated in accordance with the invention need notbe directly exposed to plasma, but may instead be exposed to corrosivegases, such as gases emitted from processed wafers or the like.Therefore, other equipment used in processing semiconductor substratescan also be provided with hafnium, strontium, dysprosium and/orlanthanum containing ceramic material surfaces and coatings according tothe invention. Such equipment can include transport mechanisms, gassupply systems, liners, lift mechanisms, load locks, door mechanisms,robotic arms, fasteners, and the like.

Examples of metallic materials that can be coated with a hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialaccording to the invention include aluminum and aluminum alloys,stainless steels and refractory metals, e.g., 6061-T6 aluminum and 304and 316 stainless steels. Because the hafnium, strontium, dysprosiumand/or lanthanum containing ceramic materials form a wear resistantcoating over the component, the underlying component is protected fromdirect exposure to the plasma. Accordingly, the metallic substrate canbe protected against erosion, corrosion and/or corrosion-erosion attackby the plasma. As a result, metallic materials, such as aluminum alloys,can be used without regard to alloying additions, grain structure Ofsurface conditions.

In addition, various ceramic or polymeric materials can also be coatedwith a hafnium, strontium, dysprosium and/or lanthanum containingceramic material according to the invention. In particular, the reactorcomponents can be made from ceramic materials, including, but notlimited to, alumina (Al₂O₃), silicon carbide (SiC), silicon nitride(Si₃N₄), boron carbide (B₄C) and/or boron nitride (BN). Polymericmaterials that can be coated are preferably those that can withstandhigh temperature conditions present in plasma reactors.

If desired, one or more intermediate layers of material can be providedbetween the surface of the substrate that is coated and the hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialcoating. FIG. 5 shows a coated component according to an exemplarypreferred embodiment of the invention. A first intermediate coating 80is optionally coated on a substrate 70 by a conventional technique. Theoptional first intermediate coating 80 is sufficiently thick to adhereto the substrate and to further allow it to be processed prior toforming an optional second intermediate coating 90, or the hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialcoating 100. The first intermediate coating 80 and the secondintermediate coating 90 can have any suitable thickness that providesthese desired properties. These coatings can have a thickness of atleast about 0.001 inches, preferably from about 0.001 to about 0.25inches, more preferably from about 0.001 to about 0.15 inches, and mostpreferably from about 0.001 inches to about 0.05 inches.

After depositing the optional first intermediate coating 80 onto thereactor component 70, the first intermediate coating can be treated,such as by roughening using any suitable technique, and then coated withthe optional second intermediate coating 90, or with the hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialcoating 100. A roughened first intermediate coating 80 provides aparticularly good bond to subsequently applied coatings. Desirably, thesecond intermediate coating 90 imparts a high mechanical compressionstrength to the first intermediate coating 80 and reduces formation offissures in the second intermediate coating 90.

The second intermediate coating 90 is sufficiently thick to adhere totie first intermediate coating 80 and to allow it to be processed priorto forming any additional intermediate coatings, or the outer hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialcoating 100. The second intermediate coating 90 also can be treated,such as by roughening. The second intermediate coating 90 can have anysuitable thickness that provides these desired properties, such as athickness of at least about 0.001 inches, preferably from about 0.001 toabout 0.25 inches, more preferably from about 0.001 and about 0.15inches, and most preferably from about 0.001 inches to about 0.05inches.

The first and second intermediate coatings can be made of any metallic,ceramic and polymer materials that are suitable for use in semiconductorplasma processing chambers. Particularly desirable metals that can beused include, but are not limited to, refractory metals, which c anwithstand high processing temperatures. Preferred ceramics include, butare not limited to, Al₂O₃, SiC, Si₃N₄, BC, AlN, TiO₂ and mixturesthereof. Preferred polymers include, but are not limited to,fluoropolymers, such as polytetrafluoroethylene and polyimides.

The intermediate coatings can be applied by any suitable depositiontechnique such as plating (e.g., electroless plating or electroplating),sputtering, immersion coating, chemical vapor deposition, physical vapordeposition, electrophoretic deposition, hot isostatic pressing, coldisostatic pressing, compression molding, casting, compacting andsintering, and thermal spraying (e.g., plasma spraying).

The optional first intermediate coating 80 and second intermediatecoating 90 can have the same or different compositions from each other,depending on their desired properties. Additional intermediate coatingssuch as a third, fourth or fifth intermediate coating of the same ordifferent materials can also be provided between the coating and thesubstrate if desired.

FIG. 6 shows another exemplary embodiment of the hafnium, strontium,dysprosium and/or lanthanum containing ceramic material coatingsaccording to the invention. The coating 100 can be deposited directlyonto a substrate, which is an outer surface of the component 70. Thecoating can be have any suitable thickness that provides the desiredlevel of wear resistance to the component. Particularly, the coating 100can have a thickness in the range of about 0.001 inches to about 1 inch,preferably from about 0.001 inches to about 0.5 inch, and mostpreferably from about 0.001 inches to about 0.05 inches. The thicknessof the ceramic layer can be selected to be compatible with the plasmaenvironment to be encountered in the reactor (e.g., etching, CVD, etc.).

As discussed above, thermal spraying is a preferred method of providingcomponents having coating surfaces according to the invention. However,other coating methods can also be used including, for example, otherdeposition techniques, such as sputtering, immersion coating, chemicalvapor deposition and physical vapor deposition; hot isostatic pressing;cold isostatic pressing; compression molding; casting; and compactionand sintering techniques.

As mentioned above, components of semiconductor processing apparatus canalso be manufactured as monolithic bodies from hafnium, strontium,dysprosium and/or lanthanum containing ceramic material. Thesemonolithic bodies can be separate bodies or coverings for othercomponents. For example, the hafnium, strontium, dysprosium and/orlanthanum containing ceramic materials according to the invention can beformed into coverings, such as liners, constructed to cover exposedsurfaces of reactor components. These coverings can be attached tosurfaces in reactor chambers by any suitable fastening technique,including, for example, adhesive bonding or by mechanical fasteners.When fasteners are used, the fasteners themselves, if exposed to theplasma, should preferably also be made from an erosion resistantmaterial to enhance their service life. Additionally, the hafnium,strontium, dysprosium and/or lanthanum containing ceramic materialcoverings may be constructed to interlock with the underlying reactorcomponent. Monolithic coverings can be provided over any suitablesubstrate, such as, for example, over walls and other surfaces.

An exemplary method of manufacturing monolithic bodies from hafnium,strontium, dysprosium and/or lanthanum containing ceramic materials mayinclude preparing a slurry containing, for example, hafnium oxide,strontium oxide, dysprosium oxide and/or lanthanum oxide; forming agreen compact in a desired shape and size from the slurry; and sinteringthe compact to form a sintered body. The green compact can be formed inthe shape of any desired plasma reactor component. Details of ceramicprocessing techniques are given in Introduction to Ceramics, 2^(nd)Edition, by W. D. Kingery, H. K. Bowen, and D. R. Uhlmann (J. Wiley &Sons, 1976). This description is incorporated herein by reference in itsentirety.

The monolithic components are preferably plasma-exposed components ofplasma reactors. Suitable components can include, for example, chamberwalls, substrate supports, gas distribution systems includingshowerheads, baffles, rings, nozzles, fasteners, heating elements,plasma screens, liners, transport module components, such as roboticarms, fasteners, inner and outer chamber walls, etc., and the like. Aspecific example of such a component is the reactor component 110 shownin FIG. 7. The reactor component 110 is a monolithic body manufacturedfrom a hafnium oxide, strontium oxide, dysprosium oxide and/or lanthanumoxide containing ceramic material.

The hafnium oxide, strontium oxide, dysprosium oxide and/or lanthanumcontaining ceramic material can be provided on all or part of thereactor chamber and components. In a preferred embodiment, the coatingor monolithic body is provided on the regions of the reactor chamberthat are exposed to the plasma environment, such as those parts indirect contact with the plasma, or parts located behind chambercomponents (e.g., liners). Additionally, it is preferred that thehafnium oxide, strontium oxide, dysprosium oxide and/or lanthanumcontaining coating or monolithic body be provided at regions of thereactor chamber that are subjected to relatively high bias voltages(i.e. relatively high sputter ion energies).

By either applying a hafnium, strontium, dysprosium and/or lanthanumcontaining ceramic coating or covering, or by constructing a monolithichafnium, strontium, dysprosium and/or lanthanum containing ceramiccomponent, in accordance with the invention, advantages are realized.Namely, lower erosion rates are achievable in plasma reactors. As aresult, the hafnium, strontium, dysprosium and/or lanthanum containingceramic coatings, coverings and components according to the inventioncan decrease levels of metal and particulate contamination, lower costsby increasing the lifetime of consumables, decrease process drifts andreduce the levels of corrosion of chamber parts and substrates.

The hafnium, strontium, dysprosium and/or lanthanum containing ceramiccoatings and components according to the invention can provide anextremely hard, wear resistant surface. Such coating or component isdesirably free of materials that react with processing chamber gases andis chemically inert such that there is low or no particle contamination,little or no corrosion, little or no metal contamination and/or littleor no volatile etch products.

While the invention has been described in detail with reference tospecific embodiments thereof, it will be apparent to those skilled inthe art that various changes and modifications can be made, andequivalents employed, without departing from the scope of the appendedclaims.

What is claimed is:
 1. A component of a semiconductor processingapparatus, comprising at least a portion comprising a ceramic material,the portion comprising an outermost surface of the component, and theceramic material comprising a material selected from the groupconsisting of lanthanum nitride and lanthanum carbide as a singlelargest constituent of the ceramic material, wherein the componentcomprises a substrate, a coating of the ceramic material over thesubstrate, and at least one intermediate layer on the substrate, whereinthe coating is over the at least one intermediate layer, and wherein thesubstrate comprises bare aluminum without an anodized surface.
 2. Thecomponent of claim 1, wherein the coating has a thickness of from about0.001 in. to about 0.050 in.
 3. The component of claim 1, wherein thecoating consists essentially of the ceramic material.
 4. The componentof claim 1, wherein the ceramic material further comprises at least onematerial selected from the group consisting of oxides, nitrides,borides, fluorides and carbides of the elements of the lanthanide seriesof the periodic table.
 5. The component of claim 1, which is selectedfrom the group consisting of a chamber wall, a chamber liner, a gasdistribution plate, a gas ring, a pedestal, an electrostatic chuck and aplasma focus ring.
 6. A plasma etch reactor comprising at least onecomponent according to claim
 1. 7. A process of manufacturing acomponent of a semiconductor processing apparatus according to claim 1,comprising applying the ceramic material as a coating over a substrate,the coating comprising an outermost surface of the component; applyingat least one intermediate layer on the substrate; and applying thecoating on the at least one intermediate layer.
 8. The process of claim7, wherein the coating consists essentially of the ceramic material. 9.The process of claim 7, further comprising at least one of: treating thesubstrate before applying the at least one intermediate layer to enhanceadhesion of the at least one intermediate layer on the substrate; andtreating the at least one intermediate layer before applying the ceramicmaterial to enhance adhesion of the ceramic material on the at least oneintermediate layer.
 10. The process of claim 7, wherein the ceramicmaterial is applied on the substrate by thermal spraying.
 11. Theprocess of claim 7, wherein the ceramic material further comprises atleast one material selected from the group consisting of (i) oxides,nitrides, borides, fluorides and carbides of the elements of Groups VA,VIA, VIIA, VIIIA, IB, IIB and IVB of the periodic table, and (ii)oxides, nitrides, borides, fluorides and carbides of the elements of thelanthanide series of the periodic table.
 12. The component of claim 1,wherein the coating is deposited by plasma spraying.
 13. The componentof claim 1, wherein the substrate comprises a roughened surface.
 14. Thecomponent of claim 1, wherein the at least one intermediate layercomprises a refractory metal, SiC, Si₃N₄, BC, AlN, TiO₂, a fluoropolymeror polyimide.
 15. The component of claim 14, wherein the fluoropolymercomprises a polytetrafluoroethylene.